The present invention generally relates to fabrication methods and resulting structures for semiconductor devices. More specifically, the present invention relates to the wet stripping of an organic planarization layer (OPL) by using ultraviolet (UV) light/rays to reversibly crosslink and de-crosslink the OPL.
Traditional CMOS (Complementary Metal Oxide Semiconductor) fabrication techniques include process flows for constructing planar transistors. The density of planar transistors can be increased by decreasing the pitch between transistor gate elements. However, the ability to decrease gate pitch in planar transistors is limited by the required gate length and spacer thickness. Nonplanar transistor architectures, such as vertical field effect transistors (VFETs) and stacked nanotube field effect transistors (FETs), employ semiconductor channels with various gate-all-around (GAA) technologies to achieve increased device density, greater power efficiency, and some increased performance over lateral devices. Photolithography is the predominant technique used to pattern these ultrafine structures. Photolithography techniques involve the patterning of a thin photoresist layer and the transfer of the resulting photoresist pattern into a substrate.